[llvm] [IR] Add block number traits to CFG (PR #102758)

[Yingwei Zheng via llvm-commits]

dtcxzyw wrote:

This patch reduces compilation time by ~1.7% on average :) https://github.com/dtcxzyw/llvm-opt-benchmark/issues/1188


https://github.com/llvm/llvm-project/pull/102758